could prework
Regular verb: prework - preworked- preworked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could prework
you could prework
he could prework
we could prework
you could prework
they could prework 	I could be preworking
you could be preworking
he could be preworking
we could be preworking
you could be preworking
they could be preworking	I could have preworked
you could have preworked
he could have preworked
we could have preworked
you could have preworked
they could have preworked	I could have been preworking
you could have been preworking
he could have been preworking
we could have been preworking
you could have been preworking
they could have been preworking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't prework
you couldn't prework
he couldn't prework
we couldn't prework
you couldn't prework
they couldn't prework 	I couldn't be preworking
you couldn't be preworking
he couldn't be preworking
we couldn't be preworking
you couldn't be preworking
they couldn't be preworking	I couldn't have preworked
you couldn't have preworked
he couldn't have preworked
we couldn't have preworked
you couldn't have preworked
they couldn't have preworked	I couldn't have been preworking
you couldn't have been preworking
he couldn't have been preworking
we couldn't have been preworking
you couldn't have been preworking
they couldn't have been preworking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I prework?
could you prework?
could he prework?
could we prework?
could you prework?
could they prework? 	could I be preworking?
could you be preworking?
could he be preworking?
could we be preworking?
could you be preworking?
could they be preworking? 	could I have preworked?
could you have preworked?
could he have preworked?
could we have preworked?
could you have preworked?
could they have preworked? 	could I have been preworking?
could you have been preworking?
could he have been preworking?
could we have been preworking?
could you have been preworking?
could they have been preworking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I prework?
couldn't you prework?
couldn't he prework?
couldn't we prework?
couldn't you prework?
couldn't they prework? 	couldn't I be preworking?
couldn't you be preworking?
couldn't he be preworking?
couldn't we be preworking?
couldn't you be preworking?
couldn't they be preworking? 	couldn't I have preworked?
couldn't you have preworked?
couldn't he have preworked?
couldn't we have preworked?
couldn't you have preworked?
couldn't they have preworked? 	couldn't I have been preworking?
couldn't you have been preworking?
couldn't he have been preworking?
couldn't we have been preworking?
couldn't you have been preworking?
couldn't they have been preworking?